Exam C7 - Remote Sensing 2015 03 page 1 of 2 CANADIAN BOARD OF EXAMINERS FOR PROFESSIONAL SURVEYORS
C7 - REMOTE SENSING & PHOTOGRAMMETRY March 2015
Although programmable calculators may be used, candidates must show all formulae used, the substitution of values into them, and any intermediate values to 2 more significant figures than warranted for the answer. Otherwise, full marks may not be awarded even though the answer is numerically correct.
Note: This examination consists of ten questions on two pages. Marks
Q. No Time: 3 hours Value Earned
1.
a) What is the maximum number of independent rotation angles needed to define a two-dimensional rotation matrix? Why?
b) Do we need Fiducial Marks in metric digital cameras? Why?
c) What are the main characteristics/differences between supervised and unsupervised classification strategies? Tabulate your answer.
d) One can argue that digital cameras can see through shadow. Do you agree with this statement? Why?
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2.
a) What are the parameters that are solved for in the following photogrammetric problems: 1) Single photo resection; 2) Photogrammetric intersection; 3) Bundle adjustment; 4) Bundle adjustment with self-calibration; 5) Dependent relative orientation for a stereo-pair; and 6) Independent relative orientation for a stereo-pair?
b) Aerial images have varying scale. Use a sketch to illustrate this fact. Sketch a special case where the scale in a photograph is considered constant.
c) How many ground control points are needed to establish the relative orientation between the images of a stereo-pair? Why?
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3.
a) Briefly explain the following terms together with the factors that control them for a given digital imaging system: 1) Radiometric resolution, 2) Spectral resolution, 3) Geometric resolution, and 4) Temporal resolution.
b) Explain how you can use the spectral reflectance curve to identify the moisture content in vegetation and soil.
c) What are the key information items you expect to have in a camera calibration certificate for a metric analog camera?
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4.
a) What is the EM radiation waveband used in RADAR remote sensing systems?
Are they active or passive systems?
b) What are the advantages of RADAR remote sensing systems?
c) What are the quantities measured by a GPS/INS system onboard an imaging platform? What are the main requirements for relating these measurements to the exterior orientation parameters of the exposure stations?
d) What are the main differences between the scene acquisition procedures for frame and line cameras?
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5.
a) What are the alternative methodologies for establishing the exterior orientation parameters of an imaging system?
b) What are the alternative methodologies for deriving the Interior Orientation Parameters (IOP) of a photogrammetric camera? Which one would you prefer to adopt? Why?
c) Classify and describe the types of points based on their role in a photogrammetric bundle adjustment procedure.
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Exam C7 - Remote Sensing 2015 03 page 2 of 2 6.
a) What is the conceptual basis of the photogrammetric Coplanarity condition?
b) What is the conceptual basis of the photogrammetric Collinearity equations?
c) Describe the conceptual basis of image smoothing in the frequency domain.
d) Describe the conceptual basis of image sharpening (enhancement) in the frequency domain.
e) What is the MINIMUM number of ground control points needed to establish the absolute orientation of a 3D model? Why?
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7.
a) What is meant by accuracy and precision?
b) What are the factors affecting the precision of the outcome from a photogrammetric bundle adjustment procedure?
c) What are the factors affecting the accuracy of the outcome from a photogrammetric bundle adjustment procedure?
d) How would you evaluate the precision and the accuracy of the outcome from a photogrammetric bundle adjustment procedure?
e) You have a digital B/W (8 bits/pixel) and a color (24 bits/pixel) image.
Comment on the radiometric and spectral resolutions of these images (i.e., which one has higher radiometric and which one has higher spectral resolution).
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8.
a) You are given a stereo-pair with thirty-nine tie points identified. List the balance between the observables and the unknown parameters in a bundle adjustment procedure to solve for the exterior orientation parameters as well as the ground coordinates of tie points. Can you estimate the involved unknown parameters? Why?
b) A distance between 2 points on a map at a scale of 1:75,000 is 31.85 mm. The distance between the same points on a vertical photo taken with a 152.04 mm focal length camera is 42.19 mm. If both points lie at an elevation of 122 meters, compute the flying height above datum.
c) What are the advantages of LiDAR remote sensing systems?
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9.
a) List the required input and necessary steps for generating an orthophoto using differential rectification.
b) How are the image coordinate systems defined in:
a. an analogue photograph acquired by an analogue metric camera, b. a digital image scanned from an analogue photograph captured by an
analogue metric camera, and
c. a digital image acquired by a digital metric camera?
c) Give a brief definition of the following entities: Nadir point, principal point, principal distance, focal length, principal planes, as well as optical axis of a lens system.
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10.
a) Where is the perspective center of the lens assembly for a digital camera system?
b) How many ground control points are needed to establish the relative orientation between the images of a stereo-pair? Why?
c) Explain how the image aberrations and distortions affect the precision and accuracy of the outcome from the photogrammetric reconstruction.
d) Where in the image is there no radial lens distortion? Why?
e) Where in the image is there no relief displacement? Why?
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2 2 Total Marks: 100
